It is well-known that during the operation of a magnetic resonance system a considerable level of noise is generated due to equipment-related operational factors. A patient undergoing examination by means of a magnetic resonance system must therefore wear a hearing protector, it being necessary to ensure in this case that the volume level at the entrance to the patient's ear (auditory canal) does not exceed 99 dBa.
A known hearing protector, often also referred to as a cap-type ear defender, consists of two ear covers that typically fit closely to the ear, or to the head around the ear, by way of padding. The covers are connected to each other via a clip which can be telescoped such that the hearing protector can be adjusted to the wearer's head size and are usually pivotably attached to the clip. Known covers consist of a hemispherical or dome-shaped, outward-curving plastic outer shell inside which there is arranged a thin inlay of foam material, the annular surface padding being arranged in the area of the shell pointing toward the head. The curvature of the generally oval outer shell is usually not symmetrical, said outer shell instead curving further outward in the lower section, which is further from the clip, than in the upper section.
A hearing protector of said kind which has a considerable width due to its design can be used in a number of examinations in which magnetic resonance systems are used because there are no space problems. In the case of examinations in the head and neck region, however, it is necessary to position special surface coils, called head coils or head-neck coils, on the patient in order to enable meaningful magnetic resonance images to be recorded. The coils, which are normally designed in the form of a cage, must be arranged as close as possible to the head of the patient in this case. A hearing protector of the type cited in the introduction cannot be used in such cases since it often cannot be worn in an appropriate manner or the coil cannot be properly positioned.
A hearing protector suitable for use in this case, implemented in the manner of headphones with a clip, is known from the German patent application 10 2004 059 678. Said hearing protector is characterized in that arranged in the plastic outer shell and permanently joined thereto is a solid inner part which consists of a dimensionally stable plastic composition and fills out the outer shell, the outer shell preferably being filled completely. Said known hearing protector is relatively slim, in other words does not bulge out too much at the sides, and offers very good acoustic insulation since the outer shell is completely filled out by the inner part.
Nonetheless, said hearing protector is likewise implemented in the manner of a headset, with the two ear covers being positioned on the outside of the ears or head, with the overall result that there is still an increase in the size of the volume to be encompassed by the head or head-neck coil due to the hearing protector being fitted.